Objective.—To evaluate the association between physical activity and all-cause mortality in postmenopausal women.

Design.—Prospective cohort study with 7 years of follow-up through December 31, 1992.

Setting and Participants.—Subjects were 40 417 postmenopausal Iowa women, aged 55 to 69 years at baseline in 1986. Physical activity was assessed by mailed questionnaire.

Main Outcome Measure.—All-cause mortality (n=2260).

Results.—After adjustment for potential confounders and excluding women who reported having cancer or heart disease and those who died in the first 3 years of follow-up, women who reported regular physical activity were at significantly reduced risk of death during follow-up compared with women who did not (relative risk [RR], 0.77; 95% confidence interval [CI], 0.66-0.90). Increasing frequency of moderate physical activity was associated with reduced risk of death during follow-up (from rarely or never engaging in activity to activity at least 4 times per week, RRs, 1.0 [referent], 0.76, 0.70, and 0.62; P value for trend<.001). A similar pattern was seen for vigorous physical activity (corresponding RRs, 1.0, 0.89, 0.74, and 0.57; Pvalue for trend=.06). Reduced risks of death with increased physical activity were evident for cardiovascular diseases (n=729) and respiratory illnesses (n=147). Women who engaged only in moderate but not vigorous physical activity also benefited, with moderate activity as infrequently as once per week demonstrating a reduced mortality risk of 0.78 (95% CI, 0.64-0.96).

Conclusions.—These results demonstrate a graded, inverse association between physical activity and all-cause mortality in postmenopausal women. These findings strengthen the confidence that population recommendations to engage in regular physical activity are applicable to postmenopausal women.